CANANDAIGUA, N.Y. (AP) — Prosecutors announced Wednesday that a grand jury had decided against bringing criminal charges against three-time NASCAR champion Tony Stewart in the August death of a driver at a sprint car race in upstate New York.

Ontario County District Attorney Michael Tantillo said the victim, Kevin Ward Jr., was under the influence of marijuana the night of the accident “enough to impair judgment.” And he said two videos examined by investigators showed “no aberrational driving by Tony Stewart.”

The decision came nearly seven weeks after Stewart’s car struck and killed Ward during a dirt track race on Aug. 9. Stewart, the brash and popular NASCAR driver known as “Smoke,” spent three weeks in seclusion following what he called a tragic accident before quietly returning to the Sprint Cup circuit. One of the biggest stars in the garage, Stewart has 48 career Cup wins in 542 starts but is winless this year and did not make the championship Chase field.

“This has been the toughest and most emotional experience of my life, and it will stay with me forever,” Stewart said in a prepared statement. “While much of the attention has been on me, it’s important to remember a young man lost his life. Kevin Ward Jr.’s family and friends will always be in my thoughts and prayers.”

Tantillo could have determined the case on his own but last week said he would take it to a grand jury. Experts said it would have been difficult to prove criminal intent, but the prosecutor asked the grand jury to consider charges of second-degree manslaughter and criminally negligent homicide.

“There were not 12 votes to either charge,” he said.

A call placed to the Ward family’s home went unanswered.

Sheriff Philip Povero spent weeks investigating, several times saying investigators did not have evidence to suggest Stewart meant to harm the other driver at the track in tiny Canandaigua. Ward had spun while racing alongside Stewart and then the 20-year-old climbed out of his car and walked down the track, waving his arms in an apparent attempt to confront the 43-year-old NASCAR veteran.

Authorities said the first car to pass Ward had to swerve to miss hitting him. The front of Stewart’s car appeared to clear Ward, but Ward was struck by the right rear tire and hurtled through the air. He died of blunt force trauma and his father later told a newspaper there was “no reason” for the death given Stewart’s skills and experience.

The sheriff asked in the days after Ward’s death for spectators to turn over photos and videos of the crash as investigators worked to reconstruct the accident. Among the things being looked at were the dim lighting, how muddy it was and whether Ward’s dark firesuit played a role in his death, given the conditions.

A fan’s video was widely circulated after Ward’s death, but details of the second video obtained by the sheriff have not been made public.

Stewart, who Povero described as “visibly shaken” after Ward’s death, vowed to cooperate in the investigation but he did not testify before the grand jury. He issued a brief statement expressing deep sadness and then dropped off the radar, missing races at Watkins Glen, Michigan and Bristol before coming back for the Aug. 31 race at Atlanta.

This July 5, 2014 photo provided by Empire Super Sprints, Inc., shows sprint car driver Kevin Ward Jr., in the vicotry lane with his car at the Fulton Speedway in Fulton, N.Y. Ward was killed Saturday, Aug. 9, 2014 at the Canandaigua Motorsports Park in Central Square, N.Y., when the car being driven by Tony Stewart struck the 20-year-old who had climbed from his crashed car and was on the darkened dirt track trying to confront Stewart following a bump with Stewart one lap earlier. (AP Photo/Empire Super Sprints, Inc.)

Looking far different then the fiery driver his fans love, Stewart quietly read a statement at a news conference in which he said the death of a driver he hit was “one of the toughest tragedies I’ve ever had to deal with.”

“This is something that will definitely affect my life forever,” Stewart said then. “This is a sadness and a pain I hope no one has to experience in their life. That being said, I know that the pain and mourning that Kevin Ward’s family and friends are experiencing is something that I can’t possibly imagine.”

Stewart’s peers were protective of him as questions emerged in the aftermath of the crash, and it pained them that Stewart was grieving in private and had cut off communication with so many of them. They welcomed him back in Atlanta, and fans gave him a robust cheer, too. Two days later during the race, his No. 14 Chevrolet slammed into the wall twice and Stewart settled for a dismal 41st-place finish.

After Ward’s death, NASCAR announced a rule that prohibits drivers from climbing out of a crashed or disabled vehicle — unless it is on fire — until safety personnel arrive. The series also cleared the way for Stewart to make its Chase for the Sprint Cup championship with a win, despite missing the three races.

Stewart, who is from Columbus, Indiana, has long been one of the most proficient drivers in racing, winning in every kind of series, from sprint cars to the elite Sprint Cup Series. He has for years taken part in little races in nondescript towns because he loves the thrill of the high horsepower, lightweight cars skidding around the dirt.

He rarely made his schedule public, popping up when he pleased, and he was welcome at the clay track at Canandaigua Motorsports Park the night before the NASCAR race in nearby Watkins Glen.

There have been very few criminal prosecutions stemming from incidents that occur during competition.

There have been two cases in the last 14 years in which NHL players were charged for their actions on the ice. Marty McSorley was convicted of assault with a weapon for hitting Donald Brashear with a stick during a 2000 game, and Todd Bertuzzi pleaded guilty to assault causing bodily harm for punching Colorado’s Steve Moore in 2004.

But it’s extremely rare for incidents during auto races to bring police scrutiny and Povero emphasized that his was an “on-track crash investigation.”

Research by The Associated Press dating to 2003 turned up no cases in which a driver was charged for his role in an on-track incident. Team owner James Sink was found guilty of misdemeanor assault of driver Maynard Peters after a bloody 2005 post-race fight in North Carolina. In 2003, NASCAR driver Jimmy Spencer was under investigation for assault after punching Kurt Busch in the face following a race at Michigan, but Busch asked for his complaint to be dropped.

Legal experts believe the case against Stewart would have been very difficult to prove.

“Death happens in a very dangerous sport, and this was driver vs. driver and Ward stepped on the track,” said David Weinstein, a former state and federal prosecutor in Miami who is now in private practice. “The only person who really knows what happened is Tony Stewart, and it’s impossible for a prosecutor to get inside his head.”

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Fryer reported from Charlotte, North Carolina. Researcher Rhonda Shafner in New York contributed to this report.

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